| Title |
Characteristics of Impulse Discharges in Wet Soil |
| Authors |
김회구(Kim, Hoe-Gu) ; 이복희(Lee, Bok-Hee) |
| DOI |
https://doi.org/10.5370/KIEE.2017.66.2.363 |
| Keywords |
Impulse voltages ; Ground resistance ; Soil ionization ; Z-t curves ; V-I curve ; Breakdown voltage |
| Abstract |
This paper presents the experimental results related to soil ionization and electrical breakdown in a concentric hemispherical electrode system under lightning impulse voltages. Dynamic voltage-current and impedance-time characteristics of soil ionization were measured and analyzed. Also the electrical breakdowns of the soil gap were investigated. The time-lag to the peak current corresponds to the soil ionization propagation. The time of ionization propagation in wet sand is found to decrease with increasing the impulse currents. A drastic decrease in ground resistance was observed during the impulse current spreading in sand. The electrical breakdown appears at the wave tail of impulse voltage and results in a wide scatter in V-t curves. The voltage-current curves have a fan-like shape attributed to ionization processes which result in increasing current and decreasing voltage. |